Duluth was cold, even before the Serpentfall; after it, the place froze. But there were shipyards, and icebreakers, and plenty of coal and iron ore to the north, and — most importantly — surface vessel hulls (and even a submarine!) that could be completed to protect the cargo ore ships that kept Duluth alive and not frozen solid. ‘Mayor’ George Johnson has yet to have any sort of formal election, but he’s popular enough to not worry about that.

Besides, Duluth has other problems. There’s something under the ice, at the far north of Lake Superior: and it’s big enough to menace and occasionally destroy merchantmen trying to trade Duluth coal and iron. After one attack in 1946 decimated a Northwestern Mutual trade fleet fleeing to Duluth from newly-Communist Milwaukee, Mayor Johnson chartered Northwestern’s Ed Fitzgerald to create a permanent naval escort squadron.

Admiral Fitzgerald has his work cut out for him. Duluth’s existing converted sub chaser fleet is easily enough to keep pirates well away from Duluth, but the northern Great Lakes are frozen more often than not these days. Regular icebreaker runs are necessary, but the icebreakers can and do attract that aforementioned something. Survivor reports are hazy, but the term ‘Ice Worm’ — or worms — seem consistent enough. Luckily, the Ice Worm does seem to be repelled, or at least hindered, by various Freemason symbols; most of the city belongs to one Lodge or another at this point, although it’s not required of anyone.

But the real equalizer for Duluth is its one functional submarine (the Arcadia). It’s encountered the Ice Worm three times, and was able to see it off every time with torpedoes. Unfortunately, Duluth’s ability to manufacture more torpedoes is limited. Mayor Johnson and Admiral Fitzgerald have thus devised a plan to lure the Ice Worm close with a cargo freighter loaded with explosives, detonate it, and thus destroy the Ice Worm once and for all. They just need somebody enough crazy and skilled enough to actually execute the plan.